Special Issue - 2018 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 NCESC - 2018 Conference Proceedings Indoor Positioning System using Ultrasound
Ananth Srish Kadaba Ankush S Department of Electronics and Communication, Department of Electronics and Communication, VVCE, Mysuru, Karnataka, India, VVCE, Mysuru, Karnataka, India,
Anusha R Bhat, V Manisha Maheshwari, Department of Electronics and Communication, Department of Electronics and Communication, VVCE, Mysuru, Karnataka, India, VVCE, Mysuru, Karnataka, India,
T P Surekha, Girijamba D L Department of Electronics and Communication, VVCE, Department of Electronics and Communication, VVCE, Mysuru, Karnataka, India Mysuru, Karnataka, India
Abstract— An Indoor Positioning system (IPS) is a system used signals with respect to the reference area are used to detect the to locate objects or people within an indoor environment using position. Indoor positioning system can be divided into three various technologies. Various technology options for the design phases in deriving location information, as shown in figure 1. of an IPS may be ultrasonic(US), infrared (IR), radio-frequency (RF) based systems which may be radio-frequency identification (RFID), received signal strength (RSS) of RF signals, Bluetooth, wireless local area network (WLAN), ultra-wideband (UWB), camera based vision analysis etc. This paper presents the design of an indoor installable beacon system with the user interface being a hand-held positioning device. The beacon system involves a serial network of ultrasound transceivers within a fixed area of consideration referred by grid matrix. Using TDoA of ultrasound signals and Multilateration algorithms, the position of the object within the grid system can be obtained. This location information can be viewed by the user in a graphical LCD display setup on the handheld device. Fig1. Basic Structure of IPS
Keywords--Indoor Positioning system, TDoA, Ultrasonic In the first phase in deriving location, sensing devices module HC-SR04, Multilateration make use of any type of signals like US, RF, IR or Vision to measure the physical quantity for location. These signals I. INTRODUCTION travel between transmitters and receivers and also carry co- An Indoor positioning system (IPS) is analogous to the ordinate information of reference nodes determining the Global positioning system (GPS) except that GPS is used for physical quantity of signals to be measured. positioning at a global scale while IPS is used for a smaller In the second phase, various methods are applied to indoor area to obtain higher precision positioning. We have calculate the physical quantity like measuring time of arrival been relying on applications like Google Maps, Apple Maps, (TOA), time different of arrival (TDOA), angle of arrival Here maps by Nokia, etc., on a daily basis. Accepting the fact (AOA), received signal strength (RSS) etc. [2]. A brief that these interfaces have been very useful to us, we must explanation of some of these measurement methods, are as consider its extension into indoor environments, so that this follows: location convenience is extended into buildings to provide a point to point guidance system. GPS cannot be used indoors Time of Arrival (ToA): This method of measurement is due to high signal attenuation from structures. Thus, there is a based on the fact that, the distance between sender and requirement to design a point to point guidance system rather receiver of a signal can be determined using the than a place to place guidance system as offered by GPS. IPS measured signal propagation time and known signal has been under extensive research from the past decade. It is velocity. tried to achieve with different technologies or a congregation of multiple technologies. Yet, there is no established standard Time Distance of Arrival (TDoA) : It is a measurement for IPS [1]. technique used in direction finding and navigation, in which the time of arrival of any signal, at physically separate receiving stations are calculated with properly II. BASIC STRUCTURE OF AN IPS synchronized time references. TDOA method calculates The basic structure of an indoor positioning system location from the differences of the arrival times involves a network of Access points (APs), which acts as a measured on pairs of transmission paths between the reference, and transmission and reception of some kind of target and fixed terminals. signals from these APs. Different characteristics of these
Volume 6, Issue 13 Published by, www.ijert.org 1 Special Issue - 2018 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 NCESC - 2018 Conference Proceedings
Angle of Arrival (AoA): This method of measurement B. Arduino Uno depends on the direction of signal propagation and is The Arduino Uno is a microcontroller board based on the typically achieved using an array of antennas or ATmega328 microcontroller. It has 14 digital input/output microphones. The angle between a signal and some pins, with 6 used as PWM outputs, 6 analog pins, a 16 MHz reference forms the orientation of the measurement. The crystal oscillator, a USB connection, an ICSP header, a power spatial separation of antennas or microphones leads to jack, and a reset button. It can be powered by simply differences in arrival times, amplitudes, and phases, connecting to a computer using USB cable, with an AC-to-DC which are used to find the distances. adapter or battery. Received Signal Strength (RSS): It is based on the fact In this system, the Arduino Uno acts as a computational that a signal decays with distance traversed. It is used by and processing unit to employ multilateration algorithms to many devices which measure the signal strength with obtain object location. received signal strength indicator (RSSI) and uses this data to find the distances or location of a device based on the signal strength it has received from the transmitter. Basically it is expressed by Friis transmission equation and in practice, it is affected by factors such as attenuation multipath propagation effects, reflections, noise, etc., In the third phase, with the raw information of a physical quantity measured, various techniques and algorithms are used which transform raw data into usable position information. Techniques have been classified as triangulation, trilateration, multilateration and fingerprinting. To implement this algorithm for location estimation some processing unit is required. Fig 1. Arduino Uno Incorporating this basic information, the system of discussion in this paper uses C. CC2500 Ultrasound signals as the physical quantity, which is The CC2500 is a low-cost 2.4 GHz transceiver designed generated through an ultrasound beacon system. for very low-power wireless applications. This module is used TDoA (Time difference of arrival) as the to transmit the data or information wirelessly from the beacon measurement method. system to handheld device. Multilateration (Multiple known points are used to locate an unknown point), as the algorithm for location estimation with the Arduino Uno as the functioning processor unit.
III. COMPONENTS INVOLVED
A. HC-SR04 Fig 4. CC2500 RF Transceiver Ultrasonic transceiver module HC - SR04 is used to emit D. SG-90 and detect ultrasonic signals of 40KHz frequency for proximity and ranging applications [3]. It provides 2cm - It is tiny and lightweight Servo motor with high output 400cm non-contact measurement function range, with the power. This servo can rotate approximately 180 degrees (90 in ranging accuracy of 3mm. The module includes ultrasonic each direction), and works just like the standard kinds but transmitters, receiver and control circuit. smaller. In this system, HC-SR04 acts as the reference access point This motor is used for directional applications which will nodes, from which ultrasound signals are communicated, to be discussed ahead. detect object location.
Fig 2: SG-90 Servo motor Fig 2. HC-SR04 Ultrasonic transceiver module
Volume 6, Issue 13 Published by, www.ijert.org 2 Special Issue - 2018 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 NCESC - 2018 Conference Proceedings
E. Nextion Display B. Handheld Device Nextion is a Human Machine Interface (HMI) display system that provides a control and visualization interface between the user and the process, machine, application or appliance. Nextion is mainly applied to IoT and consumer electronics field. It is the best solution to replace the traditional LCD and LED Nixie tube. The Nextion Editor software allows the users to create and design their own interfaces for Nextion display. In this system, the Nextion display is used for the users to view the geometric location of objects within a grid system and this forms the major component of the handheld device.
Fig 5. Handheld device block diagram
The above figures 7, 8, show the block diagram of indoor positioning system using ultrasonic modules. It is divided into two phases. First, is the beacon system and the other is handheld device. The Beacon system, consists of power supply, regulated power supply, Arduino Uno, RF transceiver, ultrasonic modules, servo motor, and buzzer, while the Handheld system Fig 3. 5” LCD Nextion Display unit consists of regulated power supply, RF transceiver and F. Other Nextion display unit. This system uses other supporting components such as a Firstly, we consider a pre-defined area for the positioning buzzer for proximity alarm application, barrel jack adapters to of the object, where we use a series of ultrasonic transceiver power the system, IC7805 voltage regulator (+5V) coupled modules which are connected to the Arduino Uno. When we with heat sinks, connecting wires and a plastic board as the power up the beacon system, the ultrasonic modules emit chassis for supporting the components and defining the range sound waves and reads back reflections within the defined of positioning. range. These measurements are sent to the Arduino where it is processed and location within the pre-defined area is obtained. IV. PROPOSED SYSTEM A buzzer and a servo motor is also connected to the Arduino for serving applications. This Arduino is powered by an A. Beacon System adapter through a 7805 voltage regulator. A pair of RF Transceivers are used on both systems, for synchronization and wireless data transfer. Arduino transfers the position data to the handheld module through the RF transceivers where the data is displayed in as a location within a grid system [4] on the LCD Nextion display screen. This handheld system is also powered by an adapter through a 7805 voltage regulator.
V. PROGRAM FLOW Before proceeding to the program flow, the main design goals of the system are defined as Location determination within the grid system.
Fig 4: Beacon system block diagram Proximity determination towards the beacons. Directing mechanism of servo motor.
Volume 6, Issue 13 Published by, www.ijert.org 3 Special Issue - 2018 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 NCESC - 2018 Conference Proceedings
On reception of data, RF module passes it to the LCD display where it is displayed within a grid system. These steps are continuously repeated to provide real- time locating feature.
VI. RESULTS AND OBSERVATIONS On implementation of the hardware and software designs, we obtain the following results with respect to our desin goals as mentioned in the previous section.
A. Location determination within the grid system
Our area of consideration is 2x2ft where we define a 12x10 grid system. On implementation, 3 grid accurate readings are achieved i.e. the original grid location along with a +1,-1 grid.
Fig 6: Programming Flowchart
A. Algorithm: Initialize all components with its respective pins. Initialize grid matrix, i.e. define the area considered. Here, it is a 2'x2' area divided into 12 rows and 10 columns of grids. Trigger the 4 ultrasonic transceivers one after the
other with a short delay between each other’s reception. Fig 7. Object being detected and located when placed in four random positions. If no reflection received for the set range, it indicates
absence of any object and the control goes back to previous step. B. Proximity determination towards beacons for security applications If reflection is received, the values of echo signal from all 4 modules are used to calculate 4 distances. If object is within 15cm from the reference node, buzzer is Multilateration and minimum distance are used to triggered. compute the numerical values of distance of the object with respect to the reference modules. C. Directing mechanism for various applications These numerical values are compared with the If an object is detected within a specified range (15cm), the reference grid system and the grid location of the servo motor directs towards the location of the detected detected object is found using geometrical methods. object. If the derived grid location is within a predefined proximity range, i.e. here the range within 15cm from the sensor modules, then the buzzer is triggered. This grid information is sent to the servo motor as feedback, to correct its direction towards the grid located within the proximity range. If the derived grid location is not within the proximity range, or has completed the buzzer triggering and servo directing functions, the location data is written serially into RF transceiver at the beacon system.
This data is transferred wirelessly to the RF Fig 8: Proximity mechanism activates buzzer and corrects servo arm transceiver on the Handheld device. direction
Volume 6, Issue 13 Published by, www.ijert.org 4 Special Issue - 2018 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 NCESC - 2018 Conference Proceedings
VII. TESTING AND VERIFICATION C. Results: (As seen from table 1) Trail number 1 indicates no detection of objected and A. Operations Testing no display, showing that there is no object within the predefined range. Trial numbers 2,3,4 indicate normal operation of setup with a 3 grid precision and with display times as show. Trial numbers 5,6 shows objected being placed between 2 grids and is displayed normally with the 3 grid accuracy Trial number 7 shows the cases where object is very close between 2 sensors such that the emitted beam angle of 30deg from hcsr04 doesn’t cover the range of object. Thus, in this trail the object is not detected. Trial number 8 shows a rare case where the object in placed exactly in the center of the setup such that it is equidistant from 2 sensors. Since, the positioning algorithm is based on minimum distance, the grids of both sensor values are displayed, giving a 6 grid accuracy. Trial numbers 9,10 shows the proximity breach cases where the object is displayed along with which the buzzer is triggered and servo motor is corrected to direct towards the object position.
Fig 9: Grid matrix divisions of considered area D. Handheld device testing Considerations: The purpose of designing a separate handheld device for B. Considerations: (As seen in figure 12) displaying the location is to provide a monitoring interface to An area of 2feetx2feet, approx. 60cm in length and the user and allow remote viewing, i.e. the user can view the breadth, is divided into a grid matrix of 12 rows results of positioning and detection, at a distance from the labelled A to L and 10 columns labeled 1 to 10, with actual beacon system setup. each grid having dimensions 5cmx5cm. For this purpose, we use a pair of CC2500 RF transceiver HC-SR04 modules are located 10cm in front of grids modules to communicate the location data wirelessly between B1, E1, H1 and K1. the beacon system and the handheld device. According to the datasheet, CC2500 has a 20m indoor range and a 40m LOS Servo motor located exactly in the middle of the range. This is tested and verified in this section along with starting row, i.e. F1 and G1. observed results. Proximity breach range set to 15cm from beacons, i.e. All measurements are made indoors i.e. within walls and within first grid row from beacon position. structures, as this is the ideal indoor environment. Object dimensions considered for testing has dimensions 4.5cmx4.5cm with 5cm height. TABLE II. TEST FOR HANDHELD DEVICE OPERATION Trial Distance between Beacon Time taken to TABLE I. TEST FOR LOCATION DETERMINATION WITHIN GRID SYSTEM number system and handheld display result (in device (in feet) seconds) Trial Grid number Grid Time taken to 1 2 2 Number on area number on display (in considered display seconds) 2 8 4 1 No object No display - 3 10 8 2 A10 ABC-10 3 4 14 10 3 L10 JKL-10 4 4 D6 CDE-6 4 5 20 18 5 D5&E5 DEF-5 5 6 30 24 6 H7&I7 HIJ-7 4 7 40 32 7 C1&D1 No display - 8 50 44 8 F5&G5 DEFGHI-5 7 9 B1 ABC-1 4 9 55 46 10 I1 GHI-1 5 10 60 49
Volume 6, Issue 13 Published by, www.ijert.org 5 Special Issue - 2018 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 NCESC - 2018 Conference Proceedings
E. Results:(As seen from table 2) considered to show two grid location output, i.e. 6 point on the As distance increases, the time taken to refresh and LCD screen, this is a rare case. display increases. As the building structure thickens due to beams or roofs, the delay is increased. Noise in encountered due to other devices operating at the same frequency (2.4GHz), such as Wi-Fi routers, Smart television etc., Best and fastest results are obtained when the handheld device is in line of sight with the beacon system, irrespective of the distance between them. Fig 12: Condition of object placed equidistant from sensors F. Constraints VIII. APPLICATIONS 1) Precision of 3 grids for reducing error rate: If precision is set to single precision on the grid, then due Geometric Positioning with Graphical location to frequent variations in the sound signals we may obtain display: A handheld device that shows the position in erroneous results. To avoid this and to get a more accurate real time can assist a person to track and locate a reading we consider a three grid precision. Also, if the particular asset. In simple geometric terms, if we position of the object is between two grids as shown in figure know the predefined coordinates of the destination 13, then single grid display will not be suitable. and recognize our coordinates, a navigational path can Hence to reduce the error rate of the results and to have a be established between them. more accurate reading we consider 3 grid precision having Used in Security systems to detect even the slightest +1,-1 grid with the actual location. movement in a specific area, hence used for Entry protection, valuable asset protection, proximity alarm, etc., Object detection and counting: By integrating this system to a counter such that it increments every time an object is detected, a counting system can be designed. This can be applicable in numerous industrial applications to reduce time consumption and human effort.
Directional surveillance: The Servo motor when Fig 10: Condition of object present between two grids integrated with a, camera provides image or video if obstacle detected, Gun or missile provides 2) Detection failure at a close distance between 2 sensors unmanned weapon system. Directional router due 30⁰ beam angle restriction: provides max signal strength towards the direction of The HCSR04 sensor that is used has a 30⁰ beam angle, so population. if any object is placed in between two sensors at a close distance as shown in figure 14, then the beam cannot reflect Robot orientation and guidance system: Autonomous back and hence the object will not be detected in such a case. systems such as robots can be guided to follow a certain path or deviate from obstacles, using ultrasound modules and ranging.
IX. CONCLUSION An indoor positioning and navigation system can make any organization more efficient, productive, and effective. Almost in every industry, one can find applications for indoor positioning system, since it makes the basis for indoor positioning, people (personal) tracking, asset tracking, etc.,
Due to its importance and increasing popularity from the last Fig 11: Condition of object being undetected decade, there is a need to research and experiment on this field. The system discussed in this paper gives a simple, low 3) If same distance from 2 sensors, both values appear: cost and efficient possibility of achieving indoor positioning. As explained earlier, the system is designed in such a way It has limitless applications like real time tracking, visitor that it considers the minimum distance to the sensors that is guidance, commercial applications, workplace safety and reference location, so if we consider a case where the object is security, asset security, surveillance etc. exactly equidistant from two sensors then both values are
Volume 6, Issue 13 Published by, www.ijert.org 6 Special Issue - 2018 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 NCESC - 2018 Conference Proceedings
X. FUTURE WORK [3] Md. Shamsul Arefin, Tajrian Mollick, "Design of an Ultrasonic Distance Meter", International Journal of Scientific & Engineering This project represents a simple demonstration of a vastly Research Volume 4, Issue3, March-2013. growing positioning technology known as the Indoor [4] Shadman Fahim Ahmad, Abrar Hasin Kamal, Iftekharul Mobin, positioning system. It is designed to obtain location "Ultrasonic Sensor Based 3D Mapping & Localization", International information and provide security applications. This system is Journal on Computer Science and Engineering (IJCSE), 2016. able to recognize the closest object to the ultrasonic nodes and [5] Ionut-Catalin Draghici, Andrei Vasilateanu, Nicolae Goga, "Indoor provide its position using minimum distance values from the positioning system for location based healthcare using trilateration with corrections", International Conference on Engineering, Technology and reference. An improvement that can be made in the existing Innovation (ICE/ITMC), 2017. system, is to be able to position multiple targets within the [6] Lih Chieh Png, Liangquan Chen, Song Liu, "An Arduino-based indoor reference area. This system does not differentiate targets. So, positioning system (IPS) using visible light communication and an upgraded system must be able to recognize the type of ultrasound", IEEE International Conference on Consumer Electronics - object present based on the obtained ultrasonic reflections. If Taiwan, 2014. we replace the ultrasonic modules any other technologies [7] S. Holm, "Airborne ultrasound data communications: the core of an which are having advanced, complex, long range and indoor positioning system", IEEE Ultrasonics Symposium, 2005 expensive nodes, we can achieve a wider range of effective [8] Xiaoqi Nong, Lei Cheng, Dai Yating, "Research on indoor navigation applications. of mobile robot based on INS and ultrosound", 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017. [9] Tan-Sy Nguyen, Thai-Hoang Huynh, "Experimental study of ACKNOWLEDGEMENTS trilateration algorithms for ultrasound-based positioning system on QNX RTOS", IEEE International Conference on Real-time Computing We would like to thank our college, Vidyavardhaka and Robotics (RCAR), 2016. college of Engineering (VVCE) and its management for [10] Sergio Sosa-Sesma, Antoni Perez-Navarro, "Fusion system based on providing us with the opportunity to carry out this project. We WiFi and ultrasounds for in-home positioning systems: The UTOPIA are thankful to our guides for providing us valuable experiment", International Conference on Indoor Positioning and suggestions, constant support and encouragement. Lastly, we Indoor Navigation (IPIN), 2016. would like to thank our parents for their unwavering love and [11] Alexander Ens, Leonhard M. Reindl, Joan Bordoy, "Unsynchronized support throughout. ultrasound system for TDOA localization", International Conference on Indoor Positioning and Indoor Navigation (IPIN), 2014. [12] Mohamed Er Rida, Fuqiang Liu, Jamal EL Merabete, "Hybrid indoor REFERENCES location system (HILS)", International Conference on Computer, Communications, and Control Technology (I4CT), 2015. [1] Ramon F. Brena, Juan Pablo García-Vázquez, Carlos E. Galván- Tejada, et al "Evolution of Indoor Positioning Technologies: A [13] Alejandro Lindo, Enrique García, Jesús Ureña, "Multiband Waveform Survey", Hindawi Journal of Sensors, Volume 2017. Design for an Ultrasonic Indoor Positioning System", IEEE Sensors Journal, 2015. [2] Mrindoko Nicholaus, Dr Lusajo M. Minga, "A Comparison Review of Indoor Positioning Techniques", International Journal of Computer (IJC), May 2016.
Volume 6, Issue 13 Published by, www.ijert.org 7